Question

if x=2 is a root of ax square+ax+6=0, find the value of a​

Answer 1

It is given that the expression ax2+bx+6=0 doesn't have distinct real roots. 

⇒ The graph of the function doesn't cross the x-axis. 

⇒ The expression f(x)=ax2+bx+6 is always greater than or equal to zero.

Hence, f(x)≥0. 

⇒ f(2)=a(2)2+b(2)+6≥0 

⇒ 4a+2b+6≥0 

⇒ 2a+b+3≥0 

⇒ 2a+b≥−3

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hope it is clear to u